A nonaqueous electrolyte battery, in which a charge and discharge are performed by migration of lithium ions between a negative electrode and a positive electrode, has been actively researched as a high energy density battery.
In addition to the use as a power supply for small electronic devices, the nonaqueous electrolyte battery is expected to be utilized also as a medium to large power source, such as for in-vehicle applications and stationary applications. The nonaqueous electrolyte battery is required to have cycle life characteristics and high stability in such medium to large size applications. The nonaqueous electrolyte battery is further required to have high input-and-output characteristics.
Examples of nonaqueous electrolyte batteries having excellent cycle life characteristics and high stability include a nonaqueous electrolyte battery in which a lithium titanate having a spinel structure is used in a negative electrode. However, since the lithium titanate having the spinel structure has a high lithium insertion-and-extraction potential of approximately 1.55 V (vs. Li/Li+), a battery voltage of a nonaqueous electrolyte battery using the lithium titanate having the spinel structure in a negative electrode is low. Further, since the lithium titanate having the spinel structure exhibits flat charge and discharge curves in the lithium insertion-and-extraction potential ranges, the lithium titanate having the spinel structure has such a feature that a change in potential accompanying a change in state-of-charge is very small.